Continuous motion washing machines, such as pot and pan washing machines of the type used in restaurants, institutions and other eating facilities, often involve a large wash tank or basin in which fluid is circulated to provide a rolling wash action for the pots, pans or other items being washed. One such machine is described in U.S. Pat. No. 4,773,436 issued to Cantrell et al., the specification of which is incorporated herein by reference. The machine of Cantrell includes a wash tank with multiple jets evenly spaced apart at an elevated position along the rear wall of the wash tank. The tank is filled with water (or other suitable wash fluid) to a level above the position of the jets. Pots and pans are placed in the wash tank, and a pump is activated to draw fluid from within the wash tank and direct it through the jets to create a jet stream. Each jet directs its jet stream toward the bottom wall of the wash tank, the bottom wall then deflects the jet stream upward and towards the front wall of the tank. The front wall then deflects the upward moving jet stream towards the rear wall of the tank, and the rear wall deflects the jet stream downward and back towards the front wall along the bottom wall. The combination of deflections of the jet stream from the bottom, front and rear walls provides a rolling washing action within the wash tank.
The basic components of the wash tank of the pot and pan washing machine of the prior art are shown in FIG. 1. Wash tank 10 includes end walls 12 and 14, rear side wall 16, front side wall 18 and bottom wall 19. A pump can be attached to either end wall; in the embodiment shown in FIG. 1, pump 50 is attached to right end wall 14. An impeller located within pump 50 is driven by electric motor 56. The impeller draws fluid into pump inlet 52 through an intake port (not shown) located in end wall 14. The fluid is then discharged from the pump through pump outlet 54 and into outlet manifold 60. Outlet manifold 60 includes a ninety degree turn, and several other turns, to direct the fluid across the back side of rear wall 16 and out jet nozzles 20 (“flow directional openings”) which are protruding through and extending from rear wall 16. The intake port associated with pump inlet 52 is covered by perforated (holes, voids, mesh, etc.) intake manifold 30. Intake manifold 30 includes handle 36 and is removably supported within wash tank 10 for easy cleaning Intake manifold 30 fits tightly between outer runner 32 and inner runner 34, each of which extends vertically from bottom wall 19. Heating element 40 is positioned between intake manifold 30 and end wall 14 for its protection and to maximize the use of space.
Although the prior art pot and pan washing machine disclosed in U.S. Pat. No. 4,773,436 provides an exceptional wash action, many of the components discussed above hinder the overall efficiency and performance of the machine. The inventions disclosed in U.S. application Ser. Nos. 09/947,484; 09/947,485; and 10/744,666, the entire disclosures of which are incorporated herein by reference, provide components that greatly increase the overall efficiency and performance of the machine, including improvements to the intake and discharge manifolds, jets, pump and system assembly methods. Nevertheless, it is often difficult to maintain suitable lifting action within the front portion of the wash tank to maintain the washing action, particularly when large, generally flat items are located toward the bottom front of the generally rectangular wash tank. Such items will tend to “stick” toward the bottom of the tank by the initial downward jet stream. The downward force from the jet stream can create a pinning action of certain types of items and these items will not roll and rotate with the wash action, resulting in these items remaining substantially soiled. In addition, as items roll and rotate within the wash tank, they often impact (with considerable force) the generally rigid steel walls of the wash tank. Such impacts result in significant noise during a wash cycle and also create unsightly and potentially harmful dents in the walls of the wash tank. In particular, dents in the bottom wall of the wash tank tend to pool water when the wash tank is drained, creating potentially unsanitary conditions. While prior art systems have been developed in which the bottom wall of the wash tank is curved (or barrel-shaped) to reduce or prevent such pinning, construction of wash tanks with such shapes is much more time consuming and expensive than construction of a generally rectangular wash tank. Moreover, it is often preferred to utilize a generally rectangular wash tank for maximizing the usable washing area within the wash tank, particularly for larger, longer items such as sheet pans. Furthermore, the generally rigid, metal walls of such curved tanks still experience significant impacts and noise during a wash cycle. Therefore, it would be beneficial to provide a washing machine, or component(s) thereof, that provide a wash action(s) that is suitable for washing a large variety of items of varying sizes, shapes and weights. It would further be beneficial to provide a washing machine, or component(s) thereof, that is cost-efficient to construct and/or that reduces impacts, noise or other vibrations action on the walls of the wash tank.